High voltage discharge tube and circuits therefor



Nov. 20, 1934. -r. E. ALLIBONE HIGH VOLTAGE DISCHARGE TUBE AND CIRCUITS THEREFOR Filed May 15, 1935 Wei:

Patented Nov. 20, 1934 STAT HIGHVOLTAGE DISCHARGE TUBE AND CIRCUITS THEREFOR Thomas Edward Allibone, Sale, England, assignor to General Electric New York Company, a corporation of Application May 15,- 1933, Serial No. mass In Great Britain May 20, 1932 c '(ci. rec-3e) This invention relates to 'high voltage electrical apparatus, such as discharge tubes, which are required to be given potential gradients in order to distribute the electrical stress on the insulating material for avoiding failures.

Thus in vacuum electricdischarge tubes having only two electrodes, namely a cathode and an anode, the full voltage arises across the gap between the electrodes but the potential gradient termined by the capacity of the various parts of the envelope to ground, the shape of the envelope and the amount of and disposition of the cathode current flowing into the tube. At very high voltages the envelope fails at points of highest stress. To overcome such difliculty it has been proposed to use sectionalized or cascade discharge tubes and to apply a predetermined voltage across each section from a sectionalized induction coil but 20 there is great dimculty in supplying energy to induction coils at very high voltages from ground. Such diiiiculty may be reduced somewhat by employing instead of an induction coil, a. Tesla high frequency generator but when this is used there are such phase displacements between the voltages of the various tappings that the utility is limited, at least for some purposes.

The present invention has for its object an arrangement wherein a cascaded discharge tube can be supplied with accurately graded potentials at very high voltages in phase.

To that end, according to the invention some or all the sections of a sectionalized cascaded discharge tube are connected to the appropriate stages of an impulse generator of that particular kind comprising a plurality of groups or stages of condensers, high resistances and spark gaps, so arranged that the condensers can be charged up in parallel through the resistances until the to spark gaps break down, whereupon series connections are established by the spark gaps and the condensers discharge in series. Such a generator is sometimes referred to as a Marx type generator and particular modifications thereof are described and claimed in the specifications of British Letters Patent No. 344,862. With the combination of discharge tube and generator above set forth, as the spark gaps of the generator break down within; 10-' second, the voltages at the various stages are all in phase.

In order that the invention may be clearlyunderstood it will now be described with reference to the accomp nying drawing, which shows ditically a sectionalized or graded electrical discharge tube connected with a high voltacross the insulating envelope is ordinarily destances to, the interior of age impulse generator of the kind above referred to in accordance with the invention.

The discharge tube shown on the right-hand side of the drawing comprises a plurality of in- I sulating envelope sections t1, t2 .tn, separated from each other by conducting members G1, G2 .Gn, for the purpose of grading the' discharge tube. The members G1, G2. .Gn may carry or be connected with conducting or accelerating tubes or plates which are indicated at y. The discharge tube may be provided at one end with an electron emitting cathode M and at the grounded end with a window P or other apparatus according to the purpose for which the discharge tube is designed. The tube may further be provided with tubulatures Q for the evacuation of, or admission of gaseous subthe discharge tube. The impulse generator which is shown on the left-hand side of the drawing is similar to the generators shown in the specifications hereinbefore referred to and comprises a. number of condensers C1, C2 .01: with associated spark gaps F1, F2. .Fn and resistances W1, W2 .Wn. The low potential leads D and E,

the latter of which may be connected to ground,

are connected to the terminal of the first spark gapFl and the high voltage lead is indicated at H. It will be understood, in accordance with the well known principles of the Marx type impulse generators that if the voltage applied to the terminals D, E is equal to V the high voltage at the output terminals H, E will be substantially equal to nV, where n is the number of condensers. The potential at the terminals of the various condensers C1; C2 .forming the stages of thegenerator will increase in accordance with the capacities of the condensers and the sparking distances of the gaps, but,

as hereinabove mentioned, the time. taken for the spark gaps F1, F2 .to break down is so very small that these voltages will be very closely in phase. Consequently if connections. are made from said condenser terminals to the appropriate members G1, G2, G3 separating the various sections of the discharge tube, a desired potential gradient from one end of the tube to the other may be maintained.

It will be understood that the specific construction of the discharge tube and of the high voltage impulse generator may be varied considerably, the drawing being purely diagrammatic and for the purpose of indicating the elements of such apparatus in a manner to enable the invention to be clearly understood.

I claim: p I 1. In combination, an electric discharge tube comprising an envelope containing a cathode and electrodes spaced along the envelope, cir-,'

cuits connected to said electrodes; said circuits including a plurality of electrical sections, each containing a sparkgap and a resistance. I

2. In combination, an electric discharge'tube comprising an envelope containing'a cathode and electrodes spaced along the envelope, circuits connected to said electrodes, said circuits-including' a plurality of electrical sections, each, containing a condenser, a spark gap and a resistance 3'. In combination, an electric discharge .tube comprising an envelope containing a cathode, an

anode and electrodes spaced along; the envelope between said cathode and anode, circuits con nected to said electrodes and anode, said-circuits including spark gapsand resistances.

4. In combination; an electric discharge tube '-comprising an envelope containing a source of electrons and electron-accelerating electrodes,

prising an envelope containing atone end, a source of electrons and including at the other end, a metal window, electron-accelerating elec-- trodes spaced along the interior oi the envelope and positioned between said source and said window; means tor applying progressively increasing'volta'ges to said electrodes "as the window is/approached, said means including a plurality of stages of high voltage impulse circuits,

each stagecontaining a spark gap and a resistance, a connection between said window and the last stage of said impulse circuits.

6. Infcombination, a cathode-ray tube con prising an envelope, containing at one-end, a

source of-electrons and including at the other end, a metal window connected to ground, electron-accelerating electrodes spaced. along the interior. of 'the envelope and positioned between said source-and said window, means for applying -progressively increasing voltages to said electrodes as the window is approached, said means including a plurality of stages of high voltage impulse circuits, each stage containing a spark gap and a resistance, a connection between said window and the last stage of said impulse circuits whereby the highest potential end of said circuits is groundedr EDWARD ALLIBONE. 

